Effects of the hypo-osmotic swelling test on the outcome of intracytoplasmic sperm injection for patients with only nonmotile spermatozoa available for injection: a prospective randomized trial

OBJECTIVE: Hypo-osmotic swelling test (HOST) has been shown to be an effective method for the selection of live sperm. On-going pregnancies were obtained by using HOST-selected sperm. The aim of this study was to evaluate the effect of using HOST-selected "live" sperm versus nonselected sperm on the outcome of intracytoplasmic sperm injection cycles when only nonmotile sperm were available for injection. DESIGN: Prospective randomized study. SETTING: Governmental tertiary care hospital. PATIENT(S): Thirty ICSI cycles with no motile sperm were included in this study. INTERVENTION(S): For the HOST group, potentially live spermatozoa detected by hypo-osmotic reaction of the tail were injected into oocytes. For the No-HOST group, the sperm were randomly injected into the oocytes without checking the viability. MAIN OUTCOME MEASURE(S): The fertilization, cleavage, embryo quality, pregnancy, and implantation rates were assessed for the two groups. RESULT(S): Among 30 cycles, 15 fall into each group. Fertilization, cleavage rates, and the number of good quality embryos were similar between two groups. CONCLUSION(S): HOST-selected live spermatozoa can be safely used for intracytoplasmic sperm injection to establish pregnancies. There is a tendency for higher pregnancy and implantation rates to result, but it does not reach statistical significance.